Recent studies have shown the effectiveness of coating diamond grains with thin layers of titanium and nickel to provide a tight interface with the nickel matrix. Wetting of diamond and nickel is improved by coating diamond particles with thin layers of titanium and nickel. Titanium carbide formed between Ti-coating and diamond provides stronger interfacial adhesion force compared to diamond micropowder with Ni-coating. To improve the thermal properties of diamond/metal composites, a metal carbide layer is needed that combines both the crystal structure and the heat transfer of heterogeneous interfaces. In modern research in coatings, in addition to TiC, attention is paid to other carbides: B₄C, V2C and VC, as well as chromium carbides. A separate direction is oxide coatings on diamonds. The mechanism of diamond protection in this direction is the predominant oxide donor behavior of Mo–B–C coatings for the formation of a stable oxide layer on the diamond surface. Diamond films with three different grain sizes were grown on the surface of a titanium alloy by high-temperature chemical vapor deposition (HFCVD). The corrosion resistance of nanocrystalline diamond (NCD) films is clearly higher than that of microcrystalline diamond (MCD) films. But cutters with intact MCD coating demonstrate the longest service life. Attention has been paid to coatings applied to hard alloys and steels, with researchers mainly focusing on coatings containing titanium, namely TiAlN, TiN/CrN and Al2O3/TiO2.